The invention is related to the field of data storage, and in particular, to a tape cartridge transport magazine that stores and shuffles tape cartridges in a vertical closed loop within the magazine to position tape cartridges for selection by a cartridge picker in a tape library.
A popular device for handling large amounts of information in a data processing system is an automated tape cartridge library. Tape cartridge libraries store and manage multiple tape cartridges containing magnetic tape media on which data is stored. Tape cartridge libraries typically include a plurality of fixed tape cartridge storage locations, at least one read/write tape drive, and a tape cartridge retrieval/transport mechanism, known in the art as a xe2x80x9ccartridge picker.xe2x80x9d
Cartridge pickers automatically exchange individual tape cartridges between the storage locations and the tape drive(s). One example of a cartridge picker includes a rotatable robotic arm with an optical sensor for selecting and retrieving a tape cartridge and transporting the tape cartridge to the tape drive(s). Another example of a cartridge about a pivot in a rotary motion to select, retrieve, and transport tape cartridges to the tape drive(s).
The tape drive(s) is typically mounted within or juxtaposed to the tape cartridge library. The tape drive(s) is operable to read/write data to or from the magnetic tape media in the tape cartridge. A host computer communicates with a library control unit and the tape drive(s) to control the operation of the tape cartridge library.
Unfortunately, tape cartridge libraries suffer from numerous drawbacks. One major drawback is their overall size, primarily due to the necessity of storing a large number of tape cartridges. In tape libraries, the tape cartridge storage locations are arranged in predetermined arrays of uniquely identified cells with each cell containing a single tape cartridge. In some cases, the array of cells is configured in a bookshelf arrangement. This type of arrangement, however, requires the use of a multi-axis cartridge picker that translates along an x, y, and/or z axis to exchange individual tape cartridges with the tape drive(s).
In other cases, such as disclosed in U.S. Pat. No. 5,847,897, the array of cells are vertically oriented in a carousel style cartridge magazine that rotates about a central axis to position tape cartridges for selection by a stationary cartridge picker. Unfortunately, the vertical orientation of the tape cartridges in the magazine, while necessary to the operation of the carousel, and use of a stationary cartridge picker, significantly adds to the overall height of the library. Additionally, the vertical orientation of the tape cartridges requires that the tape drive(s) also be vertically oriented to permit the picker to pass a tape cartridge from the magazine to the drive without a complicated re-orientation of the cartridge, further increasing the form factor size of the of the library.
The present invention solves the problems outlined above and advances the art by providing a tape cartridge transport magazine for a tape cartridge library, termed tape cartridge autoloader/library system herein. The tape cartridge transport magazine receives and stores tape cartridges in a horizontal orientation relative to the tape cartridge transport magazine to achieve a substantially smaller form factor of the tape cartridge autoloader/library system. Additionally, once loaded into the magazine, the tape cartridges are shuffled in a vertical closed loop between a top portion and a bottom portion of the magazine so that any tape cartridge within the magazine can be positioned for selection by the cartridge picker. When used with a tape cartridge autoloader/library system as disclosed herein, a pair of interchangeable magazines can be utilized to store and provide tape cartridges to a rotating cartridge picker.
A first advantage of the present tape cartridge transport magazine is that the horizontal orientation of the cartridges in the magazine permits construction of a tape cartridge autoloader/library system in a substantially smaller form factor. An autoloader/library system configured with one or more of the present magazines is architected such that the components therein are substantially coplanar. In one example, an autoloader/library system can be constructed that measures less than three and one half inches in height and fits in a standard rack mount cabinet. A second advantage of the present tape cartridge transport magazine is that the use of the vertical closed loop transport mechanism to position tape cartridges for selection by the cartridge picker limits the travel required for the exchange of tape cartridges between the magazines and the tape drive(s). In prior art systems, the cartridge picker must move to the storage location of a desired tape cartridge, select the tape cartridge from the storage location, move to the location of the tape drive and load the tape cartridge into the tape drive. As one skilled in the art will greatly appreciate, these operations are time consuming and require the use of complex mechanisms to move the cartridge picker within the autoloader/library system. In contrast, the present cartridge picker is permitted to simply rotate between the magazine(s) and at least one tape drive, while desired cartridges are delivered by the magazine(s) to the cartridge picker. Advantageously, this provides for a fast and efficient exchange and inventory of tape cartridges within an autoloader/library system. A third advantage of the present tape cartridge transport magazine is that its operation is independent of other components in the autoloader/library system. The magazine(s) can be inventorying or queuing cartridges for retrieval by the picker while the picker shuttles tape cartridges between various locations in the autoloader/library system and the one or more tape drives read and write data to a tape cartridge. A fourth advantage of the present tape cartridge transport magazine is that where multiple magazines are used, the magazines are interchangeable so that any one of the multiple magazines will interface with any one of multiple magazine ports.